Navigating instrument



July 31, 1923.

1,463,373 H. c. RoEsER NAVIGATING INSTRUMENT Filed Sept. 5. 1919 'YIIIIII 1 1 llgnq will.;

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Patented July 31', 1923.

UNITED STATES HARRY C.- ROESEB, F CHICAGO, ILLINOIS.

NAVIGATING Application led September To all'whom it my conm:

Be it known that I HARRY citizen of the United gtates, residln at Ch1- cago, in the county of Cook and tate of Illinois, have invented certain new and useful Improvements in Navigating Instruments; and I do hereby declare the followin to be a full, clear, and exact descriptlon ofg the invention, such asrwill enable others vskilled in the art to whichg'trapegrtams to make and use the same. r

This invention relates to navigating instruments and particularly to compass cards and devices in conjunction therewith.

The instrument herein described has for its object and purpose the determining of the true course of a ship in navigating rom one point to another, making a correction of error, and also giving the correct compass point of a course. A further object is the simplifying and rendering more etlicient the operation of a navigators protractor and compass card, and of improving instruments for such purposes.

Referring to the drawings:

Figure 1 is a plan view of the instrument placed set for reading on a, common mariners chart.

Figure 2 is a sectional view of the instrument.

Fi re 3 is a plan view of the lower mem r indicated at A.

Figure 4 is a perspective view of shaft C.

Figure 5 is an exposed perspective of washer D.

Figure 6 is an enlarged view of the compass point divisions.

as shown in Flgures 1, 2 and 3 1s a transparent disc havin a line indicated at 7--7 in Figures 1 an 3, and an lndex 8, here indicated as an arrow the point of the index being of the same radial length as the angular gradations on the protractor upon B. U

B is a rectan r, transparent, mariners compass card aving sides perpendicular to the North-South and East-West diameters, divisions 6 thereon upon which the compass points are depicted and marginal divisions 9 and pivoted at lts center with disc A b means of a shaft runninlg through member the said shaft fixed in but having a bearing in B and a handle 12 fixed upon said shaft so that A can be held or turned without interference with the hold- C. Ronsnn, a

INSTRUMENT.

5, 1919. Serial lo. 821,858.

ing or turning of B when B is superposed over A.

Referring to Figures 4 and 5 in detail, l2 is shown as a hexa onal thumb cap nut to headed shaft 18 wit threads 13 mating the threads of the shaft pin. The head 18 on shaft 13 being rectangular and embedding in the countersink on disc A and having friction tight washer 16 thereon which washer carries sharp oints 17, can be readily and quickly assemlbled by pressing the parts together by hand. The thumb cap nut 12 by reason of the threads 13 will not press against the rectangular member B when pressure is exerted downward on the cap nut 12 but will press disc A against the chart leaving B to be freely turned.

To determlne his course a navigator places his instrument on his chart which chart for the Lpuipose of illustration herein is shown as The instrument is so placed that the arrow I will cut his present point and the point for which he is proceeding, which points are assumed for illustration, points 122 and 21 shown on the chart. Point 122 shown at 2, point 2l shown at 3 with line 7 crossin these oints. He then by pressinr upon t e hand e 12 secures the osltion o the disc A by friction upon the c art which renders the arrow line 7 immovably fixed upon points 2l and 122 and so that the arrow remains in alignment with them. He then turns the rectan lar member B until the outward edges of are parallel with the lines 'of longitude or latitude on the chart.

Divisions indicated 9 and 10 are parallel or vertical to the sides 11 of the rectan lar member B and the sides of B are paral el to the tangents at lines dividing the quadrants of the compass card and therefore divisions 9 and 10 are parallel to the said tangents. These divisions 9 and 10 are numbered on opposed sides so that the eye quickly discerns when they are cut by lines on the chart.

As illustrated on the portion of the chart and shown when the arrow line crosses points 122 and 21 and the lines of B are parallel with the lines of latitude or longitude of this chart are arrow points to 325 degrees. The navigator knows the de of variation in this region to be egrees, therefore to a reading of 325 degrees he adds 15 degrees reaching a sum of 340 degrees which is his true angular course to be followed from point 122 to reach point 21. His

e c iras before him compass point graduations outward from the angular numerals so that instantaneously he is given his true l com ass course which as shown at 6 is N. by W. Thus the navigator is given his true course in both angular degrees and points of the compass.

The duations 9 and 10 are spaced so as to con crm to the scale of the chart and. form a, ready scale and take the place of a ruler which the navigator would otherwise require for measuring distance between points.

What I claim is:

1. A navigators instrument comprising two superposed and relatively rotatable transparent members, the upper of said members havin a compass card configura- 20 tion depicted t ereon and having parallel sides per ndicular to the North-South and 'Eastest diameters of the compass respectively, said sides being graduated and said lower member having a single diametrical line withan index ad'acent the divisions of the compass on sai upper card, as and for the purposes set forth.

2. A navigators instrument comprisin a transparent fiat member havin a, centra y located, fixed, vertical pivot and a single d1- ametrical line passing through said pivot a transparent compass card having parallel raduated sides rpendicular to -the orth-South and ast-West diameters respectively, said compass card belng rota tivel mounted on said xed pivot, as and for t e purposes set forth. i

In testimony whereof I affix my signature.

HARRY C. ROESER. 

